【Java】XML文件的解析

  1 import java.io.File;
  2 import java.io.FileInputStream;
  3 import java.io.FileNotFoundException;
  4 import java.io.IOException;
  5 import java.io.InputStream;
  6 
  7 import javax.xml.parsers.DocumentBuilder;
  8 import javax.xml.parsers.DocumentBuilderFactory;
  9 import javax.xml.parsers.ParserConfigurationException;
 10 
 11 import org.w3c.dom.Document;  
 12 import org.w3c.dom.Element;
 13 import org.w3c.dom.NodeList;
 14 import org.xml.sax.SAXException;
 15 
 16 public abstract class XMLReader {
 17     // 只需要一份 documentBuilder
 18     private static DocumentBuilder documentBuilder;
 19     
 20     static {
 21         try {
 22             documentBuilder = DocumentBuilderFactory
 23                     .newInstance()
 24                     .newDocumentBuilder();
 25         } catch (ParserConfigurationException e) {
 26             e.printStackTrace();
 27         }
 28     }
 29     
 30     public XMLReader() {
 31     }
 32     
 33     // 获取Document，Document是w3c的，不要导错了
 34     public static Document openDocument(InputStream is) {
 35         Document document = null;
 36         try {
 37             document = documentBuilder.parse(is);
 38         } catch (SAXException | IOException e) {
 39             e.printStackTrace();
 40         } finally {
 41             try {
 42                 is.close();
 43             } catch (IOException e) {
 44                 e.printStackTrace();
 45             }
 46         }
 47         
 48         return document;
 49     }
 50 
 51     public static Document openDocument(String xmlPath) {
 52         InputStream is = XMLReader.class.getResourceAsStream(xmlPath);
 53         if (is == null) {
 54             try {
 55                 // 自定义异常 
 56                 throw new XMLFileNotExistException("文件[" + xmlPath+ "]不存在!");
 57             } catch (XMLFileNotExistException e) {
 58                 e.printStackTrace();
 59             }
 60         } 
 61         
 62         return openDocument(is);
 63     }
 64     
 65     public static Document openDocument(File path) {
 66         InputStream is = null;
 67         try {
 68             is = new FileInputStream(path);
 69         } catch (FileNotFoundException e) {
 70             e.printStackTrace();
 71         }
 72         return openDocument(is);
 73     }
 74     
 75     // 抽象方法，由用户自行处理得到的标签
 76     public abstract void dealElment(Element element, int index);
 77     
 78     // 抽象方法在for循环中，每次读取到一个标签，就交给抽象方法，由用户自行使用
 79     public XMLReader parse(Element element, String tagname) {
 80         NodeList nodeList = element.getElementsByTagName(tagname);
 81         
 82         for (int index = 0; index < nodeList.getLength(); index++) {
 83             Element ele = (Element) nodeList.item(index);
 84             
 85             dealElment(ele, index);
 86         }
 87         
 88         return this;
 89     }
 90     
 91     public XMLReader parse(Document document, String tagname) {
 92         NodeList nodeList = document.getElementsByTagName(tagname);
 93         
 94         for (int index = 0; index < nodeList.getLength(); index++) {
 95             Element element = (Element) nodeList.item(index);
 96             
 97             dealElment(element, index);
 98         }
 99         
100         return this;
101     }
102     
103 }

这是我们的XML文件，对其进行解析

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <Test>
 3     <class name = "第一个标签" type = "firstLable">
 4         <parameter id = "one" value = "一"></parameter>
 5         <parameter id = "two" value = "二"></parameter>
 6         <parameter id = "thr" value = "三"></parameter>
 7     </class>
 8     <class name = "第二个标签" type = "secondLable">
 9         <parameter id = "four" value = "四"></parameter>
10         <parameter id = "six" value = "五"></parameter>
11     </class>
12 </Test>

public static void main(String[] args) {
    new XMLReader() {
        
        @Override
        public void dealElment(Element element, int index) {
            String name = element.getAttribute("name");
            String type = element.getAttribute("type");
            
            System.out.println("name=" + name + "  type=" + type);
            
            new XMLReader() {
                
                @Override
                public void dealElment(Element element, int index) {
                    String id = element.getAttribute("id");
                    String value = element.getAttribute("value");
                    
                    System.out.println("	id=" + id + "  value=" + value);
                }
            }.parse(element, "parameter");
        }
    }.parse(XMLReader.openDocument("/test.xml"), "class");
}

结果如下